Born John Joseph Killion on February 9, 1859 in Greenpoint, NY. He began boxing in 1880 as Jake Kilrain to hide his identity from his parents.

Known as a durable, courageous fighter with tremendous stamina, he defeated George Godfrey (W 3), William Sheriff (W 3) and drew with Charley Mitchell (D 4) and Mike Cleary (D 4) on his way to an epic bout with heavyweight champion John L. Sullivan. In 1887 Kilrain met Jem Smith in France for the English version of the title. After 2 ½ hours of battle, the 106-round bout was declared a draw due to darkness. After the bout, Richard K. Fox, editor of the Police Gazette and Sullivan nemesis, recognized Kilrain as champion. Fox’s relationship with Sullivan was contentious following a perceived slight at a saloon and he wanted to unseat John L. The bout was arranged for July 8, 1889 in Richburg, MS under bare knuckle and London Prize Ring Rules. In one of the truly great fistic battles ever, and the last bare knuckle championship bout, after 2 hours and 16 minutes of fighting in 104-degree heat, Kilrain’s corner stopped the fight as Kilrain - his eyes nearly closed and bleeding from his nose and lips - toed the line for the 76th round. Kilrain continued boxing until 1899, meeting the likes of Jim Corbett (L 6) and Godfrey (KO 44).